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7.6 Summary of Section 7

  1. The cost of developing and testing a new vaccine is considerable; there is no incentive to develop a vaccine if there are more cost-effective or accessible ways of controlling the disease, if the population at risk cannot pay the market price, or if the disease is so rare that a vaccine would not be profitable.

  2. Organisational difficulties in the delivery of mass vaccination programmes can limit their efficacy and (in certain cases) lead to perverse effects, such as an increase in the proportion of adverse outcomes if sub-threshold vaccine coverage increases the average age at infection.

  3. Quality control procedures on vaccines must be rigorously applied to ensure that they deliver an effective dose and are not contaminated by potentially harmful material.

  4. Perceptions of risk associated with a vaccine can lead to a decline in its uptake and subsequent resurgence of the disease. The level of concern about the safety of a vaccine tends to fluctuate in an inverse relationship with the perceived level of threat from the disease it controls. As disease incidence declines, the safety of the vaccine becomes an overriding consideration.